Separation of the constituents of alloys or mixtures of metals and/or elements similar to metals



July 9, 1940. 2,207,461

P. KEMP. SEPARATION DF'THE CONSTITUEN' IS 0E ALLOYS OR MIXTURES 0F METALS AND/0R ELEMENTS SIMILAR TO METALS Filed Oct. 12, 1938 In ve wZ'or! Pa /:00 jim v,

\ Attorrzey Patented July 9, 1940 SEPARATION OF THE CONSTITUEN'l S F ALLOYS 0R MIXTURES 0F METALS AND/OR ELEMENTS SMILAR TO METALS Paul Kemp, Vienna, Germany Germany October 25, 1937 Application October 12, 1938. Serial No. 234,631

-; 6 Claims.

This invention relates to an improvement of ing removal of. the liquid from the solid liquation the known process for the decomposition of alloys and/or mixtures of metals and/or metal-like elements, by. liquation.

An object of the invention is in particular to attain a.v particularly far-reaching separation of the more easily fusible parts of the alloy or of the mixture from the parts remaining solid in the liquation. T0 A further object of the invention is an especially eil'ectiveaid to the separation of the constituents of the liquation product by the use of particularly suitable temperatures in the liquating process.

ing out of the liquation fractionally and separation of the liquation products at different temperatures. A further object of the invention is Q to facilitate the separating of certain constit- 20 'uents present in a small quantity as compared with the other constituents, of the initial materlal, during the liquation process itself.

In the decomposition of alloys or mixtures of jmetals and m'etal-like elements into constitu- 26 ents melting at different temperatures, by means of liquation, a sufllciently thorough'separation of the liquid from the solid liquation products presents considerable difliculties.

All the known liquation processes have the 30" common drawback that the separation of the liquation products is only very incomplete, since considerable quantities of the liquid portion are retained by the solid parts remaining in such.

manner that with alloys having only a small proportion of easily fusible constituents, these could not hitherto ,be separated successfully by liquation from the constituents melting at a higher temperature. This is true both for the usual process in which the alloy is heated on an d inclined furnace sole and the components thus liquefied, flow off automatically in consequence of the inclination of the sole plate, and also in the other known processes in which the carryingv out of the liquation takes place by complete melt- 45 mg of the alloys in ,a shaft made of masonry, slow cooling thereof to liquation temperature, and the draining off of the portion left liquid through a tapping hole. It is also true for the known processes in which the liquid parts are 0 filtered off from the solid constituents through a base permeable t9 the '1iquid, if necessary using a certain pressure for accelerating the passage of the liquid, e. g., by evacuating the receiver.

I have found that an astonishingly far-reach- -A further .object of the invention is the carry- I constituents and thus a practically complete separation thereof from each other even with the presence of certain constituents only in very I small quantities can be attained by pressing the 6 liquated mixture of the solid and liquid constituents against a base permeable to the latter made, for example, of porous material, or against a grating provided with interruptions, e. g. holes or slots of suitable width, under a high pressure of not less than 100 atms. pressure for example of at least 500 atm's. and preferably at least 1000 aims. The pressure can be. producedeither by compressed gas, or by mechanical means, e. g. byv letting the pressure of a press piston act on the mixture of solid and liquid constituents at the liquation temperature, the mixture being placed in a press cylinder on a base permeable to the liquid parts. The pressures necessary according .to the invention and also the desired working 20 temperatures can be attained for example by the known hydraulic presses such as are used for making lead or brass tubes.

The base mentioned here and in the claims is not to bev understood in the sense that this base mustbe underneath the liquated metal. It can be at the side or above the metal, so that the latter for example is forced in a piston press from below upward against a sieve plateclosing the press cylinder at the top.

In carrying out the invention, the procedure may, for example, be adopted that the alloy or the metal mixture to be treated is heated up to liquation temperature in the press used for the liquation and is then subjected to a mechanical or gaseous pressure or, conversely, by the alloy or the mixturebeing placed in the liquid form in the press and. after the coolingtaking place' therein to liquation temperature, being subjected to the pressure-effect. In the first case, for ex- 40 ample, when using a hydraulic press, the alloy. or the mixture can be made into blocks adapted to the dimensions of the press cylinder, by pouring into chill moulds, the blocks being then heated in the press to the liquation temperature.

It has been found that it is possible according to the invention, to attain by the use of high pressures, a practically complete separation of the liquid from the solid liquation constitutents and to thus permit with great completeness the decomposition of alloys or mixtures which contain only very little of the part fusing at a lower temperature.

The process according to the present invention is capable of very extendedapplication. It 55 presents advantages in particular in cases in which eutectic mixtures are to be separated from impure alloys of the most varied kind, either on account of their actual value or to increase, by their separation, the value or the utility for certain purposes of the remaining alloy. As examples there may be mentioned: The production of mixed tin on the one hand, and white metal containing little-lead, that is, speculum metal on the other hand, from tin alloys of the most varied kind containing lead and copper.-

Furthermore; the removal of lead from bearing metal alloys containing much tin, the removal of tin and lead from impure zinc alloys, the decomposition of hard lead alloys such'as antimony-lead alloys with or without other vmetals into, on the one hand, the eutectic suitable as writing metal and, onthe other hand, a press residue containing much antimony, as also the removal of tin and antimony from old lead.

According to one method of carrying out the invention, there can be added to the alloy or to themetal mixture to be treated, and for the purpose of removing an injurious constituent, a metal which combines with the injurious constituent and/or other constituents of the alloy or of the metal mixture in such a way that the 'separation desired is made possible. Thus, for

example, in'many cases, by the addition of a metal which combines with the constituent to be removed, forming a compound melting at a higher temperature than the other constituents of the alloy, a separation of the troublesome constituent in the solid form is made possible in the liquation. There may be mentioned as examples the removal of silver from lead by the addition of zinc and the removal of antimony from lead or tin alloys by the addition of aluminium. In consequence of the particularly thorough separation of the liquid from the solid liquation products attainable by the high pressure to be used according to the invention, particularly favourable results can also be attained with this method of carrying out the invention.

In certain cases in particular when the quantity of the constituents contained in the initial alloy and to be separated outin solid form on the liquation, is only small, it is'advisable to carry out a-combined treatment in such manner that so as not to have to subject the whole alloy to the treatment with a high pressure, the main quantity of the liquid portion is first separated in known manner, e. g. by letting this run off on inclined furnace soles or by centrifuging, or by filtering off under slight pressure, and then only the remaining liquation residue containing the solid constituents in a correspondingly increased concentration, is exposed to the action of high pressure, e.'g. by means of a compressed gas inert with respect to the alloy or by a press plunger. 'As in such cases in general the residue from the previous treatment is conveyed at once into-the press or other device serving for the subsequent treatmentunder high pressure, the necessity of heating or cooling is dispensed with, since the treatment under high pressure takes place at the same temperature as that of the preliminary treatment.

Special effects can also be attained in certain cases by a repeated pressing at difl'erent temperatures, whereby a fractionalseparation of an alloy or a metal mixture into a number of constituents is made possible. In this, the procedure may, for example, be adopted of either obtaining in the first place by liquation and pressing at higher temperature a desired substance as press residue and the proportion pressed out in liquid form being again split up by reduction of temperature and renewed pressing, or by the alloy being at first only heated to such an extent that there take place a. separation into a desired liquid constituent and a solid mixture, and after the separation of the latter by pressing this is split up by heating to a higher temperature with further renewed pressing out.

In the treatment of alloys or mixtures, the

components of which have melting points differing greatly from each other, it is frequently of advantage to carry out the pressing treatment in the sense of the invention just below the melting point of the component meltingat the higher temperature.

Examples ened on to-the upper opening of the receptacle.

6 is a heating device, e-. g. a gas burner.

Thealloy to be treated is melted for example in an iron vessel and poured in portions each of about to kgs. into the receptacle] of the press cylinder previously heated for example by means of the burner 6. The matrix 2 with the receiver 5 is then placed in position and by tightemng the screw 3, is closed tightly on to the upper opening of the receptacle. As soon as the alloy in the receptacle has cooled to the desired; liquation temperature, in which the cooling process can if necessary be prolonged by means of the heating device 5, the press piston is placed under pressure and the pressure is raised in the course of about two minutes to approximately 1500 atms. The liquid expressed liquation portion passes through the perforations of the matrixinto the container 5 where it then solidifies. After completion of the pressing-out process, the press plunger is relieved of pressure,

. the matrix after loosening the screw 3 is raised together with the container 5 and the pressed cake remaining in the receptacle is forced out by means of the press piston. The next portion of alloy can then at once be poured in and be treated in the same way as the first lot. In this manner for example 200 kgs. of metal can be easily dealt with per hour on apress operated by a single workman.

Naturally also, the procedure may be adopted of first letting the alloy placed in-the fluid state in the receptacle l solidify completely, then heating this up to liquation temperature in the press cylinder by means of the heating device 5. If necessary, the all can also be placed in the receptacle of the ess cylinder in lumps or in the form of a bidckgadapted by casting in a separate mould, to the "diameter of the receptacle,

' and this being then heated in the receptacle to Result of tests (1) From a tin alloy of 52% Sn, 21% Sb, 11% Cu, 16% Pb there are obtained in the above described manner at a temperature of between 180 and 190 C.:

(a) Using a pressure. of 1500 atms.:

Liquid portion: 35% of mixed tin with 54.5% of Sn, 3.5% of Sb, 0.2% of Cu,

41.8% of Pb. Press residue: %of speculum metal with 50.5% of Sn, 30.4% of Sb,

16.9% of Cu, 2.0% of Pb.

(b) Using pressures of 10 to 20 atms.:

Liquid portion: 25% of mixed tin of the above composition.

Press residue: of speculum metal with 51.2% of Sn, 26.89% of Sb, 14.6% of Cu and 7.4% of Pb.

(a) Using a pressure of 1500 atms.:

Liquid portion: 63% of eutectic with 3% of Sn, 13% of Sb, 84% of Pb, 37% of press residue consisting of 5% of Sn, 76% .of Sb, 19% of Pb.

(b) Using pressure of 10 to 20 atms.:

Liquid portion: 45% of eutectic of the above composition, 55% of press residue consisting of 4.3% of- 4.3% of Sn, 55.3% of Sb and 40.4% of Pb.

higher pressure a considerable more value press residue has been obtained.

What I claim is:

1. In the process of separating the constituents of metal mixtures and/or metal alloys by pressure liquation, the step comprising the separation of the liquid from the solid constituents by press extraction under a pressure of at least 500' atmospheres.

2. In the process of claim 1, which further comprises consecutively liquefying the various constituents and press extracting each liquid constituent under a pressure equal to at least 500 atmospheres.

3. In the process of claim 1 in which said metal mixture is composed of a tin alloy containing lead, the step of heating said metal mixture to obtain a liquid constituent composed of tin and a solid constituent compos d of a tin alloy substantially .free of lead, and ress extracting said liquid constituent under a pressure of at least 500 atmospheres.

4. In the process of claim 1 in which a! metal mixture is composed of a tin alloy come ing lead, the step of heating said metal mixture at a temperature from approximately C. to C. to obtain a liquid constituent composed of tin and a solid constituent composed of a tin alloy substantially free of lead, and press extracting said liquid constituent under a pressure of at least 500 atmospheres.

5. In the process for separating from an antimony-lead alloy an approximately eutectic lead and antimony alloys from lead alloys containing a substantially greater quantity of antimony and having a higher melting point comprising heating said antimony-lead alloy to a temperature of approximately 240 C. to 255 C. to form a liquid eutectic constituent containing Sn, Sb, and Pb and a solid constituent containing lead and a large quantity of antimony, and press extracting said liquid constituent under a pressure of at least 500 atmospheres.

6. In the process of separating from antimony alloyed with lead and tina lead-tin alloy and zinc substantially free of lead comprising heating said antimony-tin-lead alloy to a temperature of approximately 200 C. to 400 C. to form a solid constituent composed of zinc and a liquid constituent composed of lead and tin, and press extracting said liquid constituent under a pressure of at least 500 atmospheres.

' PAUL KEMP. 

